1. (Field of Technology)
The present invention relates to a film wrapping machine for wrapping articles with films, particularly heat-shrinkable films.
The articles which the film wrapping machine according to the present invention can handle may be any type of container such as, for example, bottles, cans or cups of any shape, for example, either cylindrical or round. The films which the film wrapping machine according to the present invention utilizes may be a protective film for minimizing any possible scattering of fragments of the container when the latter is broken or for minimizing the unauthorized opening of the container by persons other than the purchaser, or a decorative film for aesthetic purpose or for presenting commercials associated with the contents in the container.
2. (Description of the Prior Art)
It has been widely practised to wrap containers or the like with heat-shrinkable films for the purpose of protection and/or decoration. It has also been practiced to wrap the necks and the caps of the containers together with the heat-shrinkable films for the purpose of avoiding any possible accidental separation of the caps from the necks. Whatever the purpose is, the wrapping of a heat-shrinkable film cut from a roll of film into a predetermined size is hitherto carried out by turning it around a container with its opposite ends overlapping with each other, then fusionbonding the overlapping ends of the film together to form a film tube surrounding the container, and subjecting the container with the film tube to a heat-treatment so that the film tube can shrunk to fit to the container.
A film wrapping machine capable of performing the above described wrapping method is disclosed in, for example, the U.S. Pat. No. 4,245,452, issued Jan. 20, 1981, to the same assignee of the present invention, an essential portion of which machine is reproduced in FIG. 9 of the accompanying drawings for the purp the purpose of discussion of the prior art.
Referring to FIG. 9, reference numeral 300 represents a rotary turntable assembly adapted to be driven in one direction, shown by the arrow, about a support shaft 400 for transporting containers X successively from and back to an article supply station. Reference numeral 301 represents a plurality of article holders rigidly mounted on an outer peripheral portion of the rotary turntable assembly 300 in equally spaced relationship with respect to the circumferential direction of the rotary turntable assembly 300, each of said article holders 301 having a recess 302 defined therein for the receipt of the respective container X. Reference numeral 303 represents a pair of film wrapping arms carried by each article holder 301 for pivotal movement between opened and closed positions and operable to turn the film F generally around the respective container X then received in the recess 302 of the associated article holder 301. Reference numeral 304 represents a pair of follow-up arms movably carried by each article holdere 301 and operable to assist the film wrapping in association with the respective film wrapping arms 303. Reference numeral 305 represents a film supporting spatula provided for each article holder 301 and adapted to be held in contact with the side wall of the respective container X.
Although not shown, the prior art film wrapping machine also comprises a cam mechanism so designed as to permit all of the pairs of the film wrapping arms 303 and all of the pairs of the follow-up arms 304 to be successively moved between the opened and closed positions during the rotation of the rotary turntable assembly 300 about the support shaft 400 past a particular processing station and also as to permit all of the film supporting spatulas 305 to be moved up and down in synchronism with the movement of the respective pair of the film wrapping arms 303 between the opened and closed positions.
The prior art film wrapping machine of the above described construction opereates in the following manner, Assuming that the heat-shrinkable film F is supplied into the empty recess 302 in the associated article holder 301 and the respective container X is subsequently supplied onto such recess 302 with the film F positioned radially outwardly of the container X, the associated film supporting spatula 305 is lowered from above to a position where it is brought into contact with the side wall of the container X. Simultaneously therewith, the associated pair of the film wrapping arms 303 and the associated pair of the follow-up arms 304 are sequentially moved from the opened position towards the closed position to encompass the container X whereby the film F positioned inside the recess 302 and surrounding the container X in the article holder 301 is turned around the container with its opposite ends overlapping with each other and also with the film supporting spatula 305. The overlapping ends of the film F which are also overlapping the film supporting spatula 305 are then applied with an adhesive and are clamped together by a presser head pressing the overlapping ends of the film F against the film supporting spatula 305. In this way, the film F can be completely wrapped around the container with the overlapping ends thereof bonded together, and thereafter, the container having the film tube is removed out of the associated recess 302 in the article holder 301 for the transportation to the next subsequent processing station located exteriorly of the rotary turntable assembly 300.
It has subsequently been found that the prior art film wrapping machine of the type described above has a problem in that, when the film wrapping arms 303 of each pair are pivoted to the closed position to encompass the respective container X with the film turned therearound, the opposite ends of the film F are often overlapped with each other in a manner displaced in a direction longitudinally of the container X and/or slackened. Also, the necessity of each of the film supporting spatulas 305 to be moved up and down in association with the movement of the associated film wrapping arms brings about another problem in that not only is the film wrapping machine rendered to be complicated in structure, but also a high film wrapping capability is hampered.